What to use for Boot Camp?

I have a 2009 Mac Mini with only 1 GB of memory and have been running Win 7 with a loader. It works but is kinda slow. I'm thinking about going back to Windows XP. How would I go about making it genuine? I know SLP would be the way to go and usually what I would do but no BIOS for a Mac. Any one got any ideas?

I even tried running Fusion or Parallels but with only 1 GB of memory, it's even worse! Upgrading the memory in the machine is not possible since it's not mine and our company is too damn cheap!